/* pngmem.c - stub functions for memory allocation
 *
 * Last changed in libpng 1.4.2 [May 6, 2010]
 * Copyright (c) 1998-2010 Glenn Randers-Pehrson
 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
 *
 * This file provides a location for all memory allocation.  Users who
 * need special memory handling are expected to supply replacement
 * functions for png_malloc() and png_free(), and to use
 * png_create_read_struct_2() and png_create_write_struct_2() to
 * identify the replacement functions.
 */

#include "png.h"
#define PNG_NO_PEDANTIC_WARNINGS
#if defined (PNG_READ_SUPPORTED) || defined (PNG_WRITE_SUPPORTED)
    #include "pngpriv.h"

/* Borland DOS special memory handler */
    #if defined (__TURBOC__) && !defined (_Windows) && !defined (__FLAT__)
/* If you change this, be sure to change the one in png.h also */

/* Allocate memory for a png_struct.  The malloc and memset can be replaced
   by a single call to calloc() if this is thought to improve performance. */
png_voidp /* PRIVATE */
png_create_struct(int type)
{
    #ifdef PNG_USER_MEM_SUPPORTED
    return (png_create_struct_2(type, NULL, NULL));
}

/* Alternate version of png_create_struct, for use with user-defined malloc. */
png_voidp /* PRIVATE */
png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
{
    #endif /* PNG_USER_MEM_SUPPORTED */
    png_size_t size;
    png_voidp struct_ptr;

    if (type == PNG_STRUCT_INFO)
        size = png_sizeof(png_info);
    else if (type == PNG_STRUCT_PNG)
        size = png_sizeof(png_struct);
    else
        return (png_get_copyright(NULL));

    #ifdef PNG_USER_MEM_SUPPORTED
    if (malloc_fn != NULL)
    {
        png_struct dummy_struct;
        png_structp png_ptr = &dummy_struct;
        png_ptr->mem_ptr = mem_ptr;
        struct_ptr = (*(malloc_fn))(png_ptr, (png_uint_32)size);
    }
    else
    #endif /* PNG_USER_MEM_SUPPORTED */
    struct_ptr = (png_voidp)farmalloc(size);
    if (struct_ptr != NULL)
        png_memset(struct_ptr, 0, size);
    return (struct_ptr);
}

/* Free memory allocated by a png_create_struct() call */
void /* PRIVATE */
png_destroy_struct(png_voidp struct_ptr)
{
    #ifdef PNG_USER_MEM_SUPPORTED
    png_destroy_struct_2(struct_ptr, NULL, NULL);
}

/* Free memory allocated by a png_create_struct() call */
void /* PRIVATE */
png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
                     png_voidp mem_ptr)
{
    #endif
    if (struct_ptr != NULL)
    {
        #ifdef PNG_USER_MEM_SUPPORTED
        if (free_fn != NULL)
        {
            png_struct dummy_struct;
            png_structp png_ptr = &dummy_struct;
            png_ptr->mem_ptr = mem_ptr;
            (*(free_fn))(png_ptr, struct_ptr);
            return;
        }
        #endif /* PNG_USER_MEM_SUPPORTED */
        farfree(struct_ptr);
    }
}

/* Allocate memory.  For reasonable files, size should never exceed
 * 64K.  However, zlib may allocate more then 64K if you don't tell
 * it not to.  See zconf.h and png.h for more information. zlib does
 * need to allocate exactly 64K, so whatever you call here must
 * have the ability to do that.
 *
 * Borland seems to have a problem in DOS mode for exactly 64K.
 * It gives you a segment with an offset of 8 (perhaps to store its
 * memory stuff).  zlib doesn't like this at all, so we have to
 * detect and deal with it.  This code should not be needed in
 * Windows or OS/2 modes, and only in 16 bit mode.  This code has
 * been updated by Alexander Lehmann for version 0.89 to waste less
 * memory.
 *
 * Note that we can't use png_size_t for the "size" declaration,
 * since on some systems a png_size_t is a 16-bit quantity, and as a
 * result, we would be truncating potentially larger memory requests
 * (which should cause a fatal error) and introducing major problems.
 */
png_voidp PNGAPI
png_calloc(png_structp png_ptr, png_alloc_size_t size)
{
    png_voidp ret;

    ret = (png_malloc(png_ptr, size));
    if (ret != NULL)
        png_memset(ret, 0, (png_size_t)size);
    return (ret);
}

png_voidp PNGAPI
png_malloc(png_structp png_ptr, png_alloc_size_t size)
{
    png_voidp ret;

    if (png_ptr == NULL || size == 0)
        return (NULL);

    #ifdef PNG_USER_MEM_SUPPORTED
    if (png_ptr->malloc_fn != NULL)
        ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
    else
        ret = (png_malloc_default(png_ptr, size));
    if (ret == NULL && (png_ptr->flags & PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
        png_error(png_ptr, "Out of memory");
    return (ret);
}

png_voidp PNGAPI
png_malloc_default(png_structp png_ptr, png_alloc_size_t size)
{
    png_voidp ret;
    #endif /* PNG_USER_MEM_SUPPORTED */

    if (png_ptr == NULL || size == 0)
        return (NULL);

    #ifdef PNG_MAX_MALLOC_64K
    if (size > (png_uint_32)65536L)
    {
        png_warning(png_ptr, "Cannot Allocate > 64K");
        ret = NULL;
    }
    else
    #endif

    if (size != (size_t)size)
        ret = NULL;
    else if (size == (png_uint_32)65536L)
    {
        if (png_ptr->offset_table == NULL)
        {
            /* Try to see if we need to do any of this fancy stuff */
            ret = farmalloc(size);
            if (ret == NULL || ((png_size_t)ret & 0xffff))
            {
                int num_blocks;
                png_uint_32 total_size;
                png_bytep table;
                int i;
                png_byte huge* hptr;

                if (ret != NULL)
                {
                    farfree(ret);
                    ret = NULL;
                }

                if (png_ptr->zlib_window_bits > 14)
                    num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
                else
                    num_blocks = 1;
                if (png_ptr->zlib_mem_level >= 7)
                    num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
                else
                    num_blocks++;

                total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks + 16;

                table = farmalloc(total_size);

                if (table == NULL)
                {
                    #ifndef PNG_USER_MEM_SUPPORTED
                    if ((png_ptr->flags & PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
                        png_error(png_ptr, "Out Of Memory"); /* Note "O", "M" */
                    else
                        png_warning(png_ptr, "Out Of Memory");
                    #endif
                    return (NULL);
                }

                if ((png_size_t)table & 0xfff0)
                {
                    #ifndef PNG_USER_MEM_SUPPORTED
                    if ((png_ptr->flags & PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
                        png_error(png_ptr,
                                  "Farmalloc didn't return normalized pointer");
                    else
                        png_warning(png_ptr,
                                    "Farmalloc didn't return normalized pointer");
                    #endif
                    return (NULL);
                }

                png_ptr->offset_table = table;
                png_ptr->offset_table_ptr = farmalloc(num_blocks *
                                                      png_sizeof(png_bytep));

                if (png_ptr->offset_table_ptr == NULL)
                {
                    #ifndef PNG_USER_MEM_SUPPORTED
                    if ((png_ptr->flags & PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
                        png_error(png_ptr, "Out Of memory"); /* Note "O", "m" */
                    else
                        png_warning(png_ptr, "Out Of memory");
                    #endif
                    return (NULL);
                }

                hptr = (png_byte huge*)table;
                if ((png_size_t)hptr & 0xf)
                {
                    hptr = (png_byte huge*)((long)(hptr) & 0xfffffff0L);
                    hptr = hptr + 16L; /* "hptr += 16L" fails on Turbo C++ 3.0 */
                }
                for (i = 0; i < num_blocks; i++)
                {
                    png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
                    hptr = hptr + (png_uint_32)65536L; /* "+=" fails on TC++3.0 */
                }

                png_ptr->offset_table_number = num_blocks;
                png_ptr->offset_table_count = 0;
                png_ptr->offset_table_count_free = 0;
            }
        }

        if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
        {
            #ifndef PNG_USER_MEM_SUPPORTED
            if ((png_ptr->flags & PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
                png_error(png_ptr, "Out of Memory"); /* Note "o" and "M" */
            else
                png_warning(png_ptr, "Out of Memory");
            #endif
            return (NULL);
        }

        ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
    }
    else
        ret = farmalloc(size);

    #ifndef PNG_USER_MEM_SUPPORTED
    if (ret == NULL)
    {
        if ((png_ptr->flags & PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
            png_error(png_ptr, "Out of memory"); /* Note "o" and "m" */
        else
            png_warning(png_ptr, "Out of memory"); /* Note "o" and "m" */
    }
    #endif

    return (ret);
}

/* Free a pointer allocated by png_malloc().  In the default
 * configuration, png_ptr is not used, but is passed in case it
 * is needed.  If ptr is NULL, return without taking any action.
 */
void PNGAPI
png_free(png_structp png_ptr, png_voidp ptr)
{
    if (png_ptr == NULL || ptr == NULL)
        return;

    #ifdef PNG_USER_MEM_SUPPORTED
    if (png_ptr->free_fn != NULL)
    {
        (*(png_ptr->free_fn))(png_ptr, ptr);
        return;
    }
    else
        png_free_default(png_ptr, ptr);
}

void PNGAPI
png_free_default(png_structp png_ptr, png_voidp ptr)
{
    #endif /* PNG_USER_MEM_SUPPORTED */

    if (png_ptr == NULL || ptr == NULL)
        return;

    if (png_ptr->offset_table != NULL)
    {
        int i;

        for (i = 0; i < png_ptr->offset_table_count; i++)
        {
            if (ptr == png_ptr->offset_table_ptr[i])
            {
                ptr = NULL;
                png_ptr->offset_table_count_free++;
                break;
            }
        }
        if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
        {
            farfree(png_ptr->offset_table);
            farfree(png_ptr->offset_table_ptr);
            png_ptr->offset_table = NULL;
            png_ptr->offset_table_ptr = NULL;
        }
    }

    if (ptr != NULL)
    {
        farfree(ptr);
    }
}

    #else /* Not the Borland DOS special memory handler */

/* Allocate memory for a png_struct or a png_info.  The malloc and
   memset can be replaced by a single call to calloc() if this is thought
   to improve performance noticably. */
png_voidp /* PRIVATE */
png_create_struct(int type)
{
    #ifdef PNG_USER_MEM_SUPPORTED
    return (png_create_struct_2(type, NULL, NULL));
}

/* Allocate memory for a png_struct or a png_info.  The malloc and
   memset can be replaced by a single call to calloc() if this is thought
   to improve performance noticably. */
png_voidp /* PRIVATE */
png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
{
    #endif /* PNG_USER_MEM_SUPPORTED */
    png_size_t size;
    png_voidp struct_ptr;

    if (type == PNG_STRUCT_INFO)
        size = png_sizeof(png_info);
    else if (type == PNG_STRUCT_PNG)
        size = png_sizeof(png_struct);
    else
        return (NULL);

    #ifdef PNG_USER_MEM_SUPPORTED
    if (malloc_fn != NULL)
    {
        png_struct dummy_struct;
        png_structp png_ptr = &dummy_struct;
        png_ptr->mem_ptr = mem_ptr;
        struct_ptr = (*(malloc_fn))(png_ptr, size);
        if (struct_ptr != NULL)
            png_memset(struct_ptr, 0, size);
        return (struct_ptr);
    }
    #endif /* PNG_USER_MEM_SUPPORTED */

    #if defined (__TURBOC__) && !defined (__FLAT__)
    struct_ptr = (png_voidp)farmalloc(size);
    #else
    #if defined (_MSC_VER) && defined (MAXSEG_64K)
    struct_ptr = (png_voidp)halloc(size, 1);
    #else
    struct_ptr = (png_voidp)malloc(size);
    #endif
    #endif
    if (struct_ptr != NULL)
        png_memset(struct_ptr, 0, size);

    return (struct_ptr);
}


/* Free memory allocated by a png_create_struct() call */
void /* PRIVATE */
png_destroy_struct(png_voidp struct_ptr)
{
    #ifdef PNG_USER_MEM_SUPPORTED
    png_destroy_struct_2(struct_ptr, NULL, NULL);
}

/* Free memory allocated by a png_create_struct() call */
void /* PRIVATE */
png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
                     png_voidp mem_ptr)
{
    #endif /* PNG_USER_MEM_SUPPORTED */
    if (struct_ptr != NULL)
    {
        #ifdef PNG_USER_MEM_SUPPORTED
        if (free_fn != NULL)
        {
            png_struct dummy_struct;
            png_structp png_ptr = &dummy_struct;
            png_ptr->mem_ptr = mem_ptr;
            (*(free_fn))(png_ptr, struct_ptr);
            return;
        }
        #endif /* PNG_USER_MEM_SUPPORTED */
        #if defined (__TURBOC__) && !defined (__FLAT__)
        farfree(struct_ptr);
        #else
        #if defined (_MSC_VER) && defined (MAXSEG_64K)
        hfree(struct_ptr);
        #else
        free(struct_ptr);
        #endif
        #endif
    }
}

/* Allocate memory.  For reasonable files, size should never exceed
 * 64K.  However, zlib may allocate more then 64K if you don't tell
 * it not to.  See zconf.h and png.h for more information.  zlib does
 * need to allocate exactly 64K, so whatever you call here must
 * have the ability to do that.
 */

png_voidp PNGAPI
png_calloc(png_structp png_ptr, png_alloc_size_t size)
{
    png_voidp ret;

    ret = (png_malloc(png_ptr, size));
    if (ret != NULL)
        png_memset(ret, 0, (png_size_t)size);
    return (ret);
}

png_voidp PNGAPI
png_malloc(png_structp png_ptr, png_alloc_size_t size)
{
    png_voidp ret;

    #ifdef PNG_USER_MEM_SUPPORTED
    if (png_ptr == NULL || size == 0)
        return (NULL);

    if (png_ptr->malloc_fn != NULL)
        ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
    else
        ret = (png_malloc_default(png_ptr, size));
    if (ret == NULL && (png_ptr->flags & PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
        png_error(png_ptr, "Out of Memory");
    return (ret);
}

png_voidp PNGAPI
png_malloc_default(png_structp png_ptr, png_alloc_size_t size)
{
    png_voidp ret;
    #endif /* PNG_USER_MEM_SUPPORTED */

    if (png_ptr == NULL || size == 0)
        return (NULL);

    #ifdef PNG_MAX_MALLOC_64K
    if (size > (png_uint_32)65536L)
    {
        #ifndef PNG_USER_MEM_SUPPORTED
        if ((png_ptr->flags & PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
            png_error(png_ptr, "Cannot Allocate > 64K");
        else
        #endif
        return NULL;
    }
    #endif

    /* Check for overflow */
    #if defined (__TURBOC__) && !defined (__FLAT__)
    if (size != (unsigned long)size)
        ret = NULL;
    else
        ret = farmalloc(size);
    #else
    #if defined (_MSC_VER) && defined (MAXSEG_64K)
    if (size != (unsigned long)size)
        ret = NULL;
    else
        ret = halloc(size, 1);
    #else
    if (size != (size_t)size)
        ret = NULL;
    else
        ret = malloc((size_t)size);
    #endif
    #endif

    #ifndef PNG_USER_MEM_SUPPORTED
    if (ret == NULL && (png_ptr->flags & PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
        png_error(png_ptr, "Out of Memory");
    #endif

    return (ret);
}

/* Free a pointer allocated by png_malloc().  If ptr is NULL, return
 * without taking any action.
 */
void PNGAPI
png_free(png_structp png_ptr, png_voidp ptr)
{
    if (png_ptr == NULL || ptr == NULL)
        return;

    #ifdef PNG_USER_MEM_SUPPORTED
    if (png_ptr->free_fn != NULL)
    {
        (*(png_ptr->free_fn))(png_ptr, ptr);
        return;
    }
    else
        png_free_default(png_ptr, ptr);
}
void PNGAPI
png_free_default(png_structp png_ptr, png_voidp ptr)
{
    if (png_ptr == NULL || ptr == NULL)
        return;

    #endif /* PNG_USER_MEM_SUPPORTED */

    #if defined (__TURBOC__) && !defined (__FLAT__)
    farfree(ptr);
    #else
    #if defined (_MSC_VER) && defined (MAXSEG_64K)
    hfree(ptr);
    #else
    free(ptr);
    #endif
    #endif
}

    #endif /* Not Borland DOS special memory handler */

/* This function was added at libpng version 1.2.3.  The png_malloc_warn()
 * function will set up png_malloc() to issue a png_warning and return NULL
 * instead of issuing a png_error, if it fails to allocate the requested
 * memory.
 */
png_voidp PNGAPI
png_malloc_warn(png_structp png_ptr, png_alloc_size_t size)
{
    png_voidp ptr;
    png_uint_32 save_flags;
    if (png_ptr == NULL)
        return (NULL);

    save_flags = png_ptr->flags;
    png_ptr->flags |= PNG_FLAG_MALLOC_NULL_MEM_OK;
    ptr = (png_voidp)png_malloc((png_structp)png_ptr, size);
    png_ptr->flags = save_flags;
    return (ptr);
}


    #ifdef PNG_USER_MEM_SUPPORTED
/* This function is called when the application wants to use another method
 * of allocating and freeing memory.
 */
void PNGAPI
png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
               malloc_fn, png_free_ptr free_fn)
{
    if (png_ptr != NULL)
    {
        png_ptr->mem_ptr = mem_ptr;
        png_ptr->malloc_fn = malloc_fn;
        png_ptr->free_fn = free_fn;
    }
}

/* This function returns a pointer to the mem_ptr associated with the user
 * functions.  The application should free any memory associated with this
 * pointer before png_write_destroy and png_read_destroy are called.
 */
png_voidp PNGAPI
png_get_mem_ptr(png_structp png_ptr)
{
    if (png_ptr == NULL)
        return (NULL);
    return ((png_voidp)png_ptr->mem_ptr);
}
    #endif /* PNG_USER_MEM_SUPPORTED */
#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */